(a) Technical Field of the Invention
The present invention relates to an ejection and stamping device that is coupled to a vertical die-casting machine, and particularly to a device capable of carrying out stamping operation in a die casting process.
(b) Description of the Prior Art
Auto parts, ironware parts or electronic parts are often made by die casting or stamping. The die casting is carried out by pouring metal melt in a die or mold and a rough casting can be removed from the mold after the metal melt solidifies and shapes up. The rough casting often carries scrap or burring and pores on surfaces, and secondary machining is needed to for example remove the scrap or burring, polish the casting and form coatings. The stamping, on the other hand, is carried out with a die that forcibly strike a softened metal blank to shape the metal blank into a contour corresponding to the die. A stamped product has a smooth surface. These machining processes are different from each other.
Taking the die casting as an example, a regular process of the die casting is illustrated in FIG. 1, which includes the following steps:
Step 1: melt feeding (reference numeral 11), wherein a melt supplying device supplies heated and molten metal liquid into a gate of a lower die (example being given for a vertical die casting machine);
Step 2: mold closing (reference numeral 12), wherein a hydraulic mechanism drives an upper die downward to have the upper and lower dies mated and closing;
Step 3: shooting (reference numeral 13), wherein a hydraulic injection mechanism forces the metal liquid or melt within the gate into a mold cavity defined between the upper and lower dies;
Step 4: cooling (reference numeral 14), wherein the metal melt, after completely filled in the mold cavity, is cooled down to shape up;
Step 5: mold opening (reference numeral 15), wherein, after the metal melt is cooled down and shapes up, the hydraulic mechanism is operated again to drive the upper die upward thereby opening the upper and lower dies that were closed together; and
Step 6: casting ejection (reference numeral 16), wherein, during the process of opening of the dies, the rough casting is moved with the upper die to a preset position and an ejection device that is arranged by the upper die is operated to drive an ejection board to eject the casting out of the upper die.
Referring to FIG. 2, which shows the structure of a conventional ejection device, taking the vertical die casting machine as an example again, the ejection device, which is broadly designated at 2, is arranged above the upper die and comprises a base 21, a piston cylinder 22, a piston 23, and an ejection board 24. The piston cylinder 22 is centrally mounted to the base 21. An end of the piston 23 is movably received in the piston cylinder 22 and an opposite end is coupled to the ejection board 24. Thus, when the hydraulic mechanism moves the upper die to the preset position for carrying out die opening, the piston 23 inside the piston cylinder 22 drives the ejection board 24 in an opposite direction to cause ejection pins 25 that are mounted to a surface of the ejection board 24 to penetrate through the mold cavity for ejecting out the casting that is within the mold cavity.
However, the casting that is obtained with the above described casting process still needs a secondary machining, which is very time-consuming and inefficient and also adds the manufacturing costs. In addition, the design of the ejection device 2 is plain and the operation of each stroke thereof is only producing a movement opposite to the hydraulic mechanism to eject the rough casting out of the mold cavity. Improving performance of casting is not likely. Thus, further improvement is desired to make perfect.